Mobile communication systems were developed to provide the subscribers with voice communication services on the move. With the rapid advance of technologies, the mobile communication systems have evolved to support high speed data communication services beyond the early voice-oriented services.
FIG. 1 is a diagram illustrating a general mobile communication system according to the related art.
Referring to FIG. 1, the mobile communication system includes a User Equipment (UE) 100, a Radio Access Network (RAN) 120, and a core network 140.
The RAN 120 may include radio access points 110 and 115. The radio access points 110 and 115 may interact with the UE 100 through a radio interface. Other entities of the mobile communication system are primarily connected through wire links. Examples of the radio access points 110 and 115 include evolved Node B (eNB), Node B (NB) or a Radio Network Subsystem (RNS) including Node Bs, Base Transceiver Station (BTS) or Base Station Subsystem (BSS) including BTSs, and wireless access points. With some exceptions, each of the radio access points 110 and 115 is comprised of at least one cell having a predetermined area, and the UE 100 is served by the corresponding radio access point within the cell area. The cell denotes the cell of the general cellular system, and the radio access points 110 and 115 are the device of managing and controlling the respective cell but, in the present disclosure, the terms ‘cell’ and ‘radio access point’ are used interchangeably in the same meaning.
The core network 140 may include a RAN control entity 130. The RAN control entity 130 is responsible for overall control of mobility management and authentication and security. Examples of RAN control entity may include Mobility Management Entity (MME), Serving General Packet Radio Service (SGSN), etc.
In order to provide the UE 100 with a service, the mobile communication system including the radio access point 110 has to maintain the connection with the UE 100 or have the context concerning the UE 100. The mobile communication system performs handover procedure, location registration procedures, or radio connection reestablishment procedure to maintain the connection with the UE 100 or locate the context of the UE 100 at the right place.
The handover procedure is performed according to the movement of the UE 100 in the connected state or for other reasons to changes the radio access point for interaction. Examples of the other reasons may include load balancing.
The location registration procedure includes an Attach procedure and Tracking Area Update (TAU) procedure. The Attach procedure is performed when the UE 100 connects to the network or the detached UE 100 reconnects to the network. The TAU procedure may be performed in more various situations, representatively, when the UE enters a new Tracking Area (TA).
In addition to the handover procedure and location registration procedure caused by the UE mobility, those may occurs when the wireless connection between the UE 100 and the radio access point 110 is unstable so as to be inappropriate for use for a certain duration. In such a case, it is possible to perform the radio connection reestablishment procedure between the UE 100 and the radio access point 110 before or without handover procedure and location registration procedure.
Accordingly, a method and apparatus of using the radio resource efficiently in view of time reduction or resource-saving by improving the handover procedure, location registration procedure, and radio connection reestablishment procedure of the User Equipment (UE) is desired.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.